Does ip numbers persist geographically?

Question

I'm collecting the IP numbers of visitors to my website.

I use a geolocation library to convert the numbers to geographic positioning when I want to display stats about the traffic.

I don't store the physical representation, but should I?

I'm wondering if an IP number located to New York today, e.g. in two years could be positioned to San Francisco?

Ps. I'm aware about the rotation of IP numbers among browser clients (in a neighbourhood), my question is how common (if at all) it is that IP numbers "switch" cities/countries?

Answer 1

It is very common IP address being reallocated due to following scenarios.

First, ISP updates their network topology and change the IP address to different city.

Second, ISP returns the IP address range to regional registry and then reassign to another ISP.